Huperzine (HOOP-ur-zeen) A, a dietary supplement derived from the Chinese club moss Huperzia serrata, has received some interest as a potential treatment for Alzheimer's disease.
Huperzine A acts as a cholinesterase inhibitor — a type of medication that works by improving the levels of neurotransmitters in the brain. Small early studies suggest that huperzine A may improve memory and protect nerve cells, which could slow the cognitive decline associated with Alzheimer's. More studies are needed, however, to determine possible benefits and long-term risks of huperzine A.
For now, most doctors don't recommend taking huperzine A because FDA-approved cholinesterase inhibitor medications are available that have been tested for safety and effectiveness. The Alzheimer's Association recommends that you not take huperzine A if you're already taking a prescribed cholinesterase inhibitor, such as donepezil (Aricept), rivastigmine (Exelon) or galantamine (Razadyne). Taking both could cause side effects, such as nausea, vomiting, diarrhea, dizziness and muscle cramps. Consult with your doctor before starting any dietary supplement, including huperzine A.